It is generally known to extrude boards out of plastic for use in various applications including barricade boards used on construction sites and the like. It is also generally known to provide such boards with reinforced cores for added strength.
However, the walls of conventional extruded plastic boards must be made relatively thick to provide the requisite strength for these and other applications, which adds to the weight and cost of the boards. Also the ends of conventional extruded boards are left open unless covered with a separately molded cap, which adds to the cost of the boards. Providing boards with closed ends has the advantage of increased strength as well as keeping out dirt and moisture.